Automatic reclosing system for electric switches



July l, 1930. Gd w, OKEEFFE 1,769,538

AUTOMATIC RECLOSING SYSTEM FOR ELECTRIC SWITCHES Filed Nov. 20. 1923 Patented July l, 1930 uNrrED STATES APATENT OFFICE GEORGE W. OKEEFFE, or DOECHESTEE, MASSACHUSETTS, ASSIGNOE, BYKMESNE As- SIGNMENTS, To CONDTTELECTEICAL MANUFACTURING CORPORATION, OE BOSTON, MASSACHUSETTS, A CORPORATION lOF MASSACHUSETTS 4 "AUTOMATIC REC'LOSING SYSTEM FOR ELECTRIC SWITCHES Application. led November 20, 1923. Serial No. 675,964.

This invention relates to electric switches, and apparatus andy systems for automatically controlling electric switches; andhas particular reference to automaticy reclos-ing means for electric switches.

In certain types of electrical distribution systems, an electric switch controlling a par-y ticular circuit may be provided with means to efect the automatic reclosing of the switch when the switchis opened automatically by reason of an overload in its circuit. Thereclosing -means may also be arranged to reclose the switch `a certain predetermined number of times upon its overload opening and if-the vswitch again opens because ofthe persistencev of the overload, the reclosing means may then :be Oonditionedto permit the switch to remain open. n f

An object of this invention is to provide an automatic reclosing system wherein the number of reclosings ofthe switch uponoverload may be varied to suit variousconditions of the distribution system; and also wherein the time intervening between .the overload opening and the subsequent reclosing of the switch may be varied. i, Y ,y

A further object is generally 'to improve the construction and operation. of automatic reclosing apparatus andl systems.k

Fig. 1 is a schematic representation of the automatic reclosing system and a-pparatu embodying the invention. o Fig. 2 isa side elevation of a, control relay associated with the system. -f

Fig. 3 is a front elevation in detail of the speed-reducing and circuit-controlling mech-y anism of Fig. l. n

y As here shown, the electric switch associated with the invention. and'r adapted'to be opened upon overload andrepeatedly closed may comprise a three-phase switch 10, which switch is adapted to control the circuit Said switch may be provided with operating'mechanism which may includethe trippingl or opening coil 12`and the closing coil 13. An auxiliary switch' 14 is associated with the main switch 1() and is 4adapted to be moved in one direction when themain switch is closed and moved in the opposite direction when the main switch is opened.

n Said auxiliary switch may comprise a plurality of movable or bridging contact members 15, 16, 17, and 18 and said bridging members areadapted to engageand bridge the pairs of stationary contact-members 19 through'26 inclusive. `When the auxiliary switch is moved in one direction, said bridging members are adapted to engage and electrically bridge the upper pairs of contacts and when saidfmovable member is )moved in the opposite direction, said bridging members areadapted to engage and electrically bridge the'lower pairs of contacts. yBridgingy member 15 for instance, when moved into an upper position,.corresponding to the closed position of the main switch 10, is adapted to j engage the upper pair of fixed contact-memf bers 20. lVhen said bridging member is moved into a lower position, corresponding with the open position of the main switchlO, said bridging member is adapted to engage the lower set of'contact-members 19. The samemay be true in connection vwith the re'- mainig ridging members.

f Power for energizing the opening and closing coils may be taken from the auxiliary power buses 30 and 31. VVhenan overload occurs in the line 11,1the current transformers 32 may be energized sufficiently to actuate the overload relays 33 and'said relays may serve tok complete ther circuit through the fixed relay contacts 34 and the opening coil 12, the current passing from ther auxiliary bus 30 through the *conductor 35, the' opening coil 12, the conductors 36, 37 and 38, the relay-contacts 34 and the conductor 39 to the otherauxiliarybus*31. The-switch 10 may `also be opened manually bymeans including thev manually-controlled switch 40. Said switch 40, when actuated, serves to bridge or shunt the overload .relay contacts 3l and` complete the circuit between the auxiliary buses and the opening Y coil 12. The main switch 10 may also be opened upon a reduced potential in the line' 11 by means of the under voltage relay 42, the plunger 43 of which falls upon reduction of potential and bridges its conta'ts kand thereby` completes a circuit through the opening coil 12. the current passing from the conductor36 through the auxilfio CAD

iary switch contacts 2O and bridging member to conductor 45 and thence to the auxiliary bus 31. lVlien the main switch 10 in open position it may be closed manually by means including the closing switch 4T and when said switch is closed, the current passes from the auxiliary bus through the hesitating relay 4:8 and conductors 49 and 50, through the lixed contacts of the closing switch T and conductor 51 to the other auxiliary bus The hesitating relay is thereby energized to bridge its contacts 59, and complete the circuit including the closing eoil from the bus 30 through the conductor 53 and conductor st to the other auxiliary bus 31. The control system for the switch as so far described may be more or less common in the art.

In accordance with this invention, I provide means, as a reclosing relay, arranged repeatedly to close the main .switch 10 after it has been opened repeatedly by overload. Said relay may also be provided with means to vary the time period intervening between closing operations. I may also provide other means, as a disconnecting relay, to govern said reclosing relay and the number of operations thereof and thereby time the number of reclosings of the main switch 10. Both the reclosing and disconnecting relays may be similar in construction and the co1istruc tion thereof may be as illustrated in Figs. 2 and 3. As shown in these figures, the relay may comprise essentiallyY an electric motor having the frame in which the arurl ture 6 1 is rotatably supported. The motor may also include an upper and fixed pole piece 62 which may be energized by the field coil` or actuating coil, 63. A second field pole Gi may be pivotally connected with the frame 60 and may be energized by a separate field coil, er resetting coil, 65. A. spring 66 may serve to maintain said pole piece 64 yieldingly in a low position and permit the field pole to be raised by magnetic attraction when the relay is energized. 'lfhe effect of' said spring and consequently the current value for which the lower pole piece may be attracted upwardly may be varied by varying the strength ot said spring as by varying the position of the check nut 6T on the adjusting rod G8.

rlhe armature (51 may have its shaft 69 formed or provided with a worm thread 70 on the end thereotl and said worm thread is adapted to engage a worm gear 71 of a speedreducing mechanism. Said speed-reducing mecha '.m, including said worm gea is or may be supported upon the pivotcd lower pole Gel and the. upward movement thereof serres to move said worm gear into mesh with the worm thread of said shaft 69, whereby said worm gea may be driven at a reduced speed by the armature 61. Said worm gear 71 may be formed or provided with a series el apertures 'T2 therein, which apertures may be arranged concentrically with said gear. A movable circuit-controlling member is or may be arranged to be connected with said gear 71 by means of one of said apertures 72 whereby to be driven by said worm gear. Said curalt-controlling member may include the arms 73, which arms may be disposed on opposite les of said worm gear 'T1 and be pivotally supported on the shaft 74 of said worm gear. Said arms 73 may extend beyond the periphery of said worm gear and the ends thereof may be connected by the insulating circuit-controlling bar T5, which bar preferably extends laterally on opposite sides of said arms. A screw 76 may be extended removably through one of Isaid arms 73 and into one ot said apertures 72, whereby to secure said arms adjustably in dri ving connection with said worm gears. Contact-members T7 and 78 may be secured to said trame Gt) and one of said contact-members, as the contact-member 78, may extend into the path ot movement of' said insulating circuit con trolling' bar T5. The arrangement is or may be such thatA as said armature 61 is rotated with its shaft in driving engagement with the worm gear 71, said circuit-controlling bar is moved relatively slowly upward in a position to engage the contact member 78 and thereby move it to either make or break the circuit including said contact-members as may be desired. 'hen the circuit is broken, the lower pole piece G4 of the relay is adapted to be moved downward by the spring G6 and in the position shown in Fig. 2, thereby to cause the disengagement of the armature 61 and the worm gear 71. The circuit controlling member is adapted to :fall or rotate rapidly by grayity into its original or contactfree position. The angular relation between the circuit-controlling member and the contacts 7T and 7S, as determined by the particular aperture 'T2 in which the pin or screw 7G of the circuit-controlling member is in engagement, determines the time period between the successive controls of the circuit including said contact members.

The relay so tar described may constitute the reelosing relay as above mentioned. The disconnecting relay above mentioned may include the structure of the reclosing relay and, in addition, means to provide a slower rate of motion of the circuit-controlling member. The speed-reducing mechanism may include a small gear S0 fixed to the shaft 74 of the worm gear 71. Said gear S() may mesh with a large gear S1 carried by the pivoted frame which includes the lower pole piece (-l. Said gear 81 may be fixed to a small gear 82 and said small gear may be in mesh with a large gear 83, which large gear is or may be rotatably supported on the shaft T4. of the worm gear 71. Said gear 83 may be formed or provided with a series of apertures 72 therein. which apertures may correspond in manner passing from ,they

contact-members 78 `'energized from the auxiliary l f this purpose,

. said main switch member and` function to the apertures 7 2 in the worm gear 7,1. A screw 7 6 may threaded in an extension 73` of one of the arms 73 of the circuit-controlling member kwhereby said member will be driven at the this purpose, said gear S3 may be termed or yprovided with the lateral extension or pin 87 and said pinis adapted to be rotated beneath and engage the contact-member 85 and thereby raise it from engagcrn ent with the contactinember S6 andv said action preferably occurs when the disconnecting relay has been reversed to its 'normal reset position. Vv'hen the circuit-controlling member is rotated forwardly toward the other contact-members 77 and 78,-said contact-member 85 will be released and engage its cooperating contact 86 and therebyco'mplete the circuit including said contact members.

The reclosing relay A, Fig.

1, 1s arranged with normally open contact-members 77 and V7B and said members are arranged, when closed, to bridge the manually-operable closing switch 47 and connect the hesitating relay lto the yauxiliary buses 30 and 31, the current ing relay 48, conductors 49 and l90 yand closed yand 77 to conductor 91 `and l and thence to :theother auxiliary bus 31. The two field coils 68 and 65 andthe armature Glotthe reclosing relay are or may be connected in shunt and are arranged to be buses when the main vswitch 10 is opened and de-energized when said switch is closed. As yarranged for the current mayl pass from the auxiliary bus through the conductor 93, the stationary contacts 21 and the bridging contact 16 of the auxiliaryfswitch, the con- -ductor 94, the field coils andV armature of the reclosing relay and thence through conductor 95, the armature 61 of the disconnecting `relay B, and through the normally-closed contact-members 77 and 78 of said disconnecting relay and'through the conductor 96 It is thus apparent tothe auxiliary bus 31.. that each time the main switch 10 is opened automatically, as by kan overload, the reclosing relay A will operate to close its normally open contact-members 77 and 78 and etlect the re-closing of lthe 4main switch. yThen l0 is closed,'the auxiliary switch will be moved to break the circuit at the contacts 21 and thereby permit the reclosing relay to be reset. This action, not govbe dis osed to; enter in one of said apertures 72 and be disable the reclosing relay bus 30 through ythe hesitat- ,is lenergized when erned` by the disconnecting relay B,Imay continue indefinitely.

T ie disconnecting relay B is adapted to be energized each time there-closing relay is energized and move its circ uit-controlling mem-ber towards its normally closed contactineinbers 77 and 7 8 thereby to open them and A. The rate of .movement of the circuit-controlling member ot' ysaid disconnecting relay B, however, is adapted to be relatively slow ascompared to the rate oi movement of the .circuit-controlling member ot' the rcclosing relay so .that a number ot rec-losing ,operations of the reclosing nelay A may be carried ,out before the `dieconn acting relay Bk has been actuated sutliciently to disable ythe re-closing relay; and the particular number y of operations permitted or the reclosing relay A may depend upon the particular ysettings `of the circuitcontrolling members of both relays.

The disconncctin g relay B is also arranged to be positively rotated reverselyvivhen the main switch 1() is closed whereby to effect the resetting of said relay; and when the circuitcontrolling member of said relay B hasbeen restored to its normal position, the contactmembers y and 86 are adapted to be opened whereby toy prevent urt-herreverse rotation of the relay.

In carrying `out ,these features, one of the field coils of the disconnecting relay B, as f the iield coil (53, isarranged to be so connected as to rotate the armature of the disconnecting relay toward the Contact-membersV 77 and 7B. he other .fieldcoil G5 of said relay is adapted, When the main switch l() is opened, to be energized to rotate the armature in `the reverse direction and .thereby reset the relay. As here shown,jbut one of thefieldcoils is energized at a time,

the disconnecting relayhas not separatedlthe contacts Sfand 86. Vvhen the main switch 1() isl open, thecircuit iscompleted through switch, the conductor 99, thecontacts 77 and 78 of said disconnecting relay and the .conductor 96 to the auXiliarybus 31. It willbe seen that' the rcclosing and disconnecting relays are arranged in series and that the arma-k ture of `the disconnecting Arela-y isarranged Valways in shunt with one of thetield coils of the relay.

ythe ,conductor 98,

d held coils of It will be apparent that when the armature of the disconnecting relay khas been rotated forwardly for a sutlicient period of time, the circuit-controlling member thereof will have ybeen moved into a positionto ,effect ythe sep- 3ws although the armature 61 f v n the main switch 1() is opened and ,also when 1t is closed, providlng switch of the main aration of the contacts 77 and 78, and the deenergization of the armature and field coil, and also the de-energization and disabling ot the reclosing relay, whereby to leave the main switch 10 in open position. As thus arranged, the disconnectiner relay will maintain its contact-members 77 and 7 S separated and consequently the reclosing relay will be disabled and the main switch 10 will remain in open position until it is reclosed manually or by the operation of the manually-controlled closing switch 47.

lVhen the main switch 10 is reclosed manually it is desirable. at the same time, to reset or restore the disconnecting relay to its normal position, or as shown in Fig. 1. Inasmuch as the armature circuit ot the disconnecting relay is interrupted through the contact-members 77 and 7S ot' the disconnecting relay V, an auxiliary circuit is provided, and said auxiliary circuit is or may be arranged normally to bridge said open contact-members 7 7 and 78. Said auxiliary circuit is controlled by the auxiliary switch 10 and said circuit is adapted to be closed when the main switch is closed manually. Said auxiliary circuit ext-ends from the contact-member 77 of the disconnecting relay through the conductor 101 and the fixed contact-members 24 and bridging member 17 of the auxiliary switch, and through conductor 102 and the fixed contact-members 22 and bridging contact-ineinber 16 of the auxiliary switch, and thence through conductor 103 to the other contact member 7S ot the disconnecting relay, and finally to the bus 31. lVhen the main switch 10 is closed, therefore, the circuitthrough the armature 61 includes the resetting coil 65 and contact members 85 and S6 and the current passes from the auxiliary bus 30 through the conductor 105 to the contact-member S6 thence to the contact-member' 85, conductor 100. fixed contact-members 2G and movable bridging members 18 of the auxiliary switch of the main switch 10, conductor 107, armature 61 and through the auxiliary circuit including the conductors 101 and 103 to conductor 96 and thence to the auxiliary bus 31. The resetting field coil 65 is connected across the arma-ture G1 of the disconnecting relay through the circuit including the conductors 110 and 111, fixed contact-members 24 and bridging members 17 of the auxiliary switch of the main switch 10 and conductor 101. As thus arranged, the circuit is completed through the armature G1 and the resetting field coil 65 of the disconnecting relay and said armature is caused to rotate in the reverse sense and reset or restore the circuit-controlling member thereof to normal or contact-free position. Vhen the circuitcontrolling member arrives in normal position the contact-members 85 and 86 are separated thereby to interrupt the motor circuit and stop the motor from further reverse rotation. The circuits which govern the forward rotation of the disconnecting relay are not effected by the above-described control of the contact-members 85 and 86 and the relay may be forwardly rotated in the manner previously described.

The operation of the system as above described may be substantially as follows:

When the main switch 10 is opened under overload, the reclosing relay A is caused to rotate to close its contact-members 77 and 78 and efi'ect the reclosing of the switch. During the rotation of the reclosing relay, the disconnecting relay B is also caused to rotate in a forward direction or to open its normally-closed contact-members 77 and 78. Due to the iact that the reclosing relay A is arranged to move its circuit-controlling member at a higher speed than that of the disconnecting relay. the reclosing relay is adapted to effect the closing ot the main switch 10. The reclosing rel-1y thereupon cle-energized and the circuit controlling member falls by gravity to its normal position. lVhen the main switch in closed position, the disconnecting relay is caused to be rotated in a reverse sense and, ii the main switch 10 stays closed by reason of the disappearance ot' the overload, the disconnecting relay may finally rotate into a position illustrated in Fig. 1 and remain inoperative in such position as against tui-ther reverse rotation. If, however, the short circuit still persists on the line governed by the main switch 10. said switch will he again opened and reclosing relay A will again operate to reclose the main switch and disconnecting relay B will be rotated forwardly as before. It the main switch is opened and closed repeatedly by reason of the continued overload on the line, the disconnecting relay will tend to rotate reversely cach time the switch is closed. It may be, however, that, by reason of the short period of. time the main switch is closed, before it again opens, and also by reason of the inertia or the moving parts of the disconnecting relay, said relay may remain without substantial reverse rotation even though it is energized for reverse rotation. After the reclosing relay has been operated a predetermined number' of times, as determined by the respective settings of the two relays, the disconnecting relay B will have been rotated forwardly sufiicicntly to cause t-he separation of its normally closed contact members 77 and 7 8,' and the disconnecting relay will become (le-energized and maintain said contact-ineinbers separated and thereby disable the reclosing relay and consequently maintain the switch 10 open until it is manually closed.

It is to he noted that the act of reclosing the main switch serves automatically to effeet the resetting of the reclosing system. The resetting field coil 65 of the disconnecting relay may have dilerent characteristics from that of the other field coil 63 whereby the disconnecting relay may be rotated reversely or in a resetting direction at a speed which is different from its speed in a forward direction.

The operation of the switch under the overload in its circuit and under the control of thelassociated relays may be termed its duty cyc e.

The arrangement ma be otherwise modified without departing rom the spirit ofthe invention.

I claim:

1. An automatic reclosing system for an electric switch comprising means to o en the switch upon overload, means rendere effective by the opening of the switch to reclose it repeatedly against the overload, and means to hold the switch open after a number of such reclosing operations, each one of said last two means having provision for varying the number of reclosing operations of the switch Vprior to its being held open independently of f the other of said twol means.

2. An automatic reclosing system for an electric switch comprising means to open the switch upon overload, means to close the switchy including a reclosing relay which is actuated during all the time that the switch is open to close it after it has been open a predetermined time, and means including a disabling relay which is operable independently of said reclosing relay and is rendered eeetiveby the initial opening of the switch to Lmove uninterruptedly throughout the time said switch is open toward a position to ultimately disable said reclosing relay and leave the switch open, said disabling relay having self-disabling means, whereby to disable the system until reset. Y

3. An automatic reclosing system for an electric switch comprising means to open the switch uponl overload, means including a reclosing relay rendered effective by the opening of the switch to close it repeatedly, said reclosing relay including switch-controlling contact-members, a movable controlling member movable intofcontrolling relation with said contact-members, speed-reducing gearing connecting said controlling member and actuating means, actuating means for said controlling member, and means to vary the time eriod of control of said contact-members y said controlling member, means including a disconnecting relay rendered effective bv the initial opening of the switch to i f ultimatelydisable said reclosing relay and leavey the switch open, said disconnecting relay having contact-members arranged to control the operation of said reclosing relay, a controlling member for said contact members, actuating means for said controlling member, speed-reducing gearing connecting saidk actuating means and controlling member, and means to vary the time eriod of control of said contact-members trolling member.

LtAn automatic reclosing system for an electric switch comprising means to open the switch upon overload, a reclosing relay rendered effective by the opening ot the switch to close theswitch repeatedly, said reclosing relay having a relatively fast-moving switchclosing member, a disconnecting relay rendcred effective by the initial overload opening of the switch to disable said reclosing relay after a number of reclosings of the switch and leave the switch open, said disconnecting relay having a relatively slow-moving controlling member for said reclosing relay, whereby to permit said reclosing relay to close the switch repeatedly under overload prior to being disabled, and both relays having means to vary their time periods of operation.

5. An automatic reclosing system for an electric switch comprising means to open the switch -upon overload, means to close the switch including a reclosing relay rendered effective by the opening of the switch to reyclose Vit repeatedly, and means including a disconnecting relay rendered effective by the initial opening of the switch to ultimately disable said reclosing relay and leave the switch open, said disconnecting relay including contact-members arranged `to control said reclosing relay, a control-member for said contact members arranged to be driven positively into a contact-controlling position and also positively into a contact-free position, means to drive said controlling member toward a contact-controlling position when the switch is open, y and means to drive said controlling member toward a contact-free position when the switch is closed, and means including other contact members controllable by said controlling member arranged to arrest said controlling-member in a contact-free position.

6./ An automatic reclosing system for an electric switch comprising means to open the switch upon overload, means to close the switch including a reclosing relay rendered effective by the opening of the switch to reclose it repeatedly, and means including a disconnecting relay renderedk e'ective by the initial opening of the switch to ultimately disable said reclosing relay and leave the switch open, said disconnecting relay including contact-members arranged to control said reclosing relay, acontrol-member for said contactmembers arranged to be driven positively into a cont-act-controllingr position and also positively into acontact-free position, means to drive said controlling member toward a contact-controlling position when the switch is open, means to drivesaid controlling member toward a contact-free position when the switch is closed, means to arrest said controlling-member in a contact-controlling poy said conmanually-controlled said controllingsaid controlling-member in contact-free position.

7. An automatic reclosing system for an electric switch cc uprising means to open the switch upon oveload, means to close the switch including a reclosing relay which is actuated during all the time that the switch open to close itafter it has been open a predetermined time, and means including a` disconnecting relay rendered effective by the initial ogieniag of the switch to ultimately disable said reclosing' relay and leave the switch open said disconnecting relay including contatft-members arranged to control said rcclosing relay, a `controlling-member for said contact-members, means to move said controlling-member with delayed effect into a contact-controlling position including an actuating coil, means to move said controlling-member with delayed effect into a contact-free position including a re-setting coil, means rendered effective when the switch is open to energize said actuating coil, and means rendered effective when the switch is closed to ein. gine said resetting coil.

S, An automatic reclosing system for an electric switch comprising means to open the switch upon overload, means to close the switch including a reclosing relay which is actuated during all the time that the switch is open to close it after it has been open a predetermined time, and means including a disconnecting relay rendered effective by the initial opening ot' the switch to ultimately disable said reclosing relay and leave the switch open, said disconnectingl relay` including contact-members arranged to control said reclosing relay, a controlling member for said contact-members, means to move said controlling-member with delayed effect into a contate-controlling position including an actuating` coil, means to move said controlling-member with delayed effect into a contact-tree position including aresetting coil, means rendered effective when the switch is open to energize said actuating coil, means rendered efiective when the switch is closed to energize said resetting coil, and means governed by said controlling-member in contact.- :tree position to cle-energize said resetting coil.

9. An automatic reclosing system for an electric switch comprising means to open the s vitch upon overload, means to close the switch including a reclosing relay which is actuated during all the time that the switch is open to close it after it has been open a predetermined time, and means including a disconnecting relay rendered effective by the initial opening of the switch to ultimately disable said rcclosing relay and .leave the switch open, said disconnecting relay including contact-members arranged to control said reclosing relay, a controlling member for said contact-member, means rendered effective when the switch is open and including an electric motor arranged to move said controlling-member with delayed effect into a contact-controlling position, whereby to disable said reclosing relay and leave the switch open, means rendered effective when the switch is closed to reverse the direction of rotation of said motor and move said controlling-member with delayed effect into a contact-free position, and means to de-energize said motor with said controlling-member in contact-free position.

10. An automatic reclosing system for an electric switch comprising means to open the switch upon overload, means to close the the switch including a reclosing relay which is actuated during all the time that the switch is open to close it after it has been open a predetermined time, and means including a disconnecting relay rendered effective by the initial opening of the switch to ultimately' disable said reclosing relay and leave the switch open, said disconnecting relay including contact-members arranged to control said reclosing relay, a controllingmember for said contact-members, and means to move said controlling-member with delayed effect into a contact-controlling position and also into a contact-free position comprising an electric motor, said motor having a rotatable armature arranged in driving relation with said controlling member, and two field coils therefor, means rendered effective by the open condition of the switch to energize the armature and one field coil, whereby to drive said controlling-member into contact-controlling position and disable said reclosing relay and means rendered effective by the closed condition of the switch to energize the armature and the other field coil, whereby to reverse the direction of rotation of the armature and drive the controlling-member toward a contact-free position, and means governed by said controlling-member in contact-free position to deenergize said motor.

1l. An automatic reclosing system for an electric switch including means to open the switch upon overload, means rendered effective by the opening of the switch to rcclose it repeatedly, and means movable continuously toward an operative position when the switch is open to ultimately render said reclosing means inoperative and to hold the switch open.

l2. An automatic reclosing system for an electric switch, comprising means to open the switch upon overload, means to close the switch including a reclosing relay which is actuated during all the time that the switch is open to close it after it has been open a f predetermined time, and means including a name to this 

